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LUCIAN W. BUGBEE, 0F INDIANAPOLIS, INDIANA, ASSIG-NOR. TO ONEPIECEBIFOCAL LENS COMPANY, OF INDIANAPOLIS, INDIANA, A CORPORATION.

PROCESS OF FINISHING THE SURFACES 0F LENSES OR THE LIKE.

No Drawing.

To all whom it may concern:

Be it known'that I, LUOIAN W. BUGBEE, a citizen of the United States,and a resident of Indianapolis, county of Marion, and State of Indiana,have invented a certain new and useful Process of Finishing the Surfacesof Lenses or the like; and I do hereby declare that the following is afull, clear, and exact description thereof.

The object of this invention is to improve the finished surfaces. ofoptical and other lenses requiring a highly finished surface.

The chief feature of the invention consists in simultaneously'polishingand chemically treating the lens surface, or, in other words, chemicallytreating the lens surface while it is being polished, with the resultthat the nature of the lens is changed in such a way as to lower itsreflection coefficient.

The reflection percentage P of a glass surface is directly related tothe refractive indeX n, as stated in the formula ('n if P I (n 1") andany means whereby the refractive index can be changed for the surface ofthe glass will change the reflection coefficient. 5

The foregoing is a well-known scientlfic fact and it is not new to treatglass surfaces chemically after the same has been polished. 'As thenature of the glass surface changes rapidly after polishing, it hasSpecification of Letters Patent.

Application filed March 12, 1919. Serial No. 282,207.

Patented Sept. so, rare.

material is in liquid form and is applied to the glass surface whilebeing polished and finished.

The polishing material may be any suitabl'e material heretofore used forpolishing the surfaces of lenses for finishing the same, and also thechemical may be any suitable chemical producing the effect desired, butin practice I have used a solution of hydrogen sulfid in ammonia mixedwith iron peroxid and water, but I do not wish to limit myself to theseparticular ingredients.

One advantage gained by the simultaneous polishing and chemicaltreatment is that the heat generated in the surface of the glass by thefriction during the polishing thereof and the mechanical effect ofrubbing said surface, materially facilitates the desired chemicalaction. Thereby it is possible during the polishing operation, .bymixing certain chemicals with the polishing material, to moreefiectively and satisfactorily lower or change the reflectioncoeflicient of the glass.

Also another result which is obtained by changing the chemical nature ofthe surface of'the glass is the so-called selective absorption, whereby,because of the chemical change efi'ected during the above-mentionedsimultaneous polishing and chemical treatment, certain wave lengths oflight, which previously would have been freely transmitted, are, afterthis operation, selectively absorbed. Therefore, with this process oneis able, at the same time that he lowers or changes the reflectioncoefiicient of the surface of the glass, to obtain a desired andpredetermined selective absorption.

The invention claimed is:

1. In the process of finishing a glass surface, heating the glasssurface, and at the same time applying thereto a chemical adapted tolower the reflection coefficient of said surface.

2. In the process of finishing a glass surface, simultaneously polishingand chemically treating said surface.

, 3. In the process of finishing a glass sur face, mixing polishingmaterial and a chemlface, mixing suitable polishing material and calmaterial adapted to lower the reflection a solution of hydrogen sulfidin.ammonia. coefficient of the glass surface, and then In Witnesswhereof I have-hereunto affixed polishing the glass surface with saidcommy signature. 5 bined materials.

4. In the process of finishing a glass sur- LUCIAN W. BUGBEE.

